Java Runtime类详解_动力节点Java学院整理

//此实例来自《java核心技术》卷一 class MemoryDemo{     public static void main(String args[]){         Runtime r = Runtime.getRuntime();         long mem1,mem2;         Integer someints[] = new Integer[1000];         System.out.println("Total memory is ：" + r.totalMemory());         mem1 = r.freeMemory();         System.out.println("Initial free is : " + mem1);         r.gc();         mem1 = r.freeMemory();         System.out.println("Free memory after garbage collection : " + mem1);         //allocate integers         for(int i=0; i<1000; i++) someints[i] = new Integer(i);          mem2 = r.freeMemory();         System.out.println("Free memory after allocation : " + mem2);         System.out.println("Memory used by allocation : " +(mem1-mem2));          //discard Intergers         for(int i=0; i<1000; i++) someints[i] = null;         r.gc(); //request garbage collection         mem2 = r.freeMemory();         System.out.println("Free memory after collecting " + "discarded integers : " + mem2);     } }